Worm cutting machine



Dec. 17, 1940. J. R; RICHER 2,224,988

' WORM CUTTING MAQHINE Filed Apr`l 2l, 1957 5 SheetSSheeb 1 1NvENToR. BY .Tese/Z272 7E. jczer ATTO EYS.

yc., 17, J, R RlCHER 2,224,988

WORM CUTTING MACHINE `Filecl April 2l, 1957 5 Sheets-Sheet 2 INVENTOR.v

ATTORNEY.5

I Dec., 17, 3.940. J, R RICHER 2.224,988

WORM CUTTING MACHINE v Filed April 2l, 1937 5 Sheets-Sheet 3 INVENTOR;

.fosa/6k E 231.6567" ATTORNEYS.

Dec. l?, w49. J. R. RlcHx-:R

WORM CUTTING MACHINE Filed April 21, 1937 5 sheets-sheet 4 llllllLllil ,lluluv mlm.

INVENTOR. osef. /'Ogz ATTOR Dec. 17, 1940. J. R. RICHER WORM CUTTING MACHINE Filed. April 2l, 1937 5 Sheets---Sheefl 5 `HJVENTOR Jose/5k 7C?. 7156567' y om@ Patented Dec. 17, 1940 UNITED vSTATES 2,224,988 Y, WORM CUTTING Aimrcniiva a corporation of Ohio Application April'Zl, 1937, Serial No. 138,159

7 Claims.

The present invention relates toga machine forcutting worms of the hour glass type, a1- ternatvely known as globoid and Hindley worms. More particularly, the invention relates to an 5f apparatus for making such worms, employing `the molding, generating principle, and wherein a cutterof less diameter and having a less numberjof teeth than the worm wheel with which the nished worm is intended to mesh is rotated about its Own axis in timed relation with the rotation of the worm or Work, and is also traversed through acurved path or orbit correspondingto the contour o-f the pitch line of the iinished worm.

One of the objects oi my invention is to provide means for so varying and controlling the path of the orbit through which the axis of the cutter travels as to produce a worm whose pitch line has a varying radius of curvature. Such pitch line in the threads adjacent its ends is greater than the radius of curvature of the pitch line of the threads in its intermediate portion are particularly vwell adapted for use in automotive vehicle steering gear mechanisms, wherein it is desired to have the worm wheel or segment corresponding theretoy make an initially close I it with the intermediate portion of the threads of the worm anda loose iit with the. end portions of such threads so that subsequent wear which is usually concentrated and is greatest at the intermediate threads can be subsequently adjusted after a period of use without producing a binding action on the end threads of the worm.

Brieily outlined, my invention comprises means for rotating the work or worm blank, rotating a gear shaped cutter about its own axis in timed relation with the rotation of the worm and also about a parallel removedaxs or through an orbit parallel to the pitch line of the iinished worm, together with means for controlling the path and degree of curvature of such orbit. Additional objects and advantages of the invention shall become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed vout in the claims.

The annexed drawings and the following idescription set forth in detail certain mechanism embodyingthe invention, such disclosed lmeans constituting, however, but one of various mechanical forms in which thejprinciple of the invention may be used. v

worms, wherein the radius of curvature of the In said annexed drawings:

Fig. 1 'is an. elevational view, partially in section, jof an apparatus embodying the principle of my invention; Fig. 2 is an enlarged sectional a View of thatportion of the apparatus shown in 'l Fig. l comprising 'the cutter mounting andoperating mechanism; Fig. 3 is a transverse sectional view taken substantially along vline 3-3 ofiFig. 2; Fig. 4 'is a transverse sectional View taken along line "II-4 of Fig. 2; Fig. 5 is a top l0 plan view of the portion ofthe apparatus shown in Fig. 2; Fig. 6 is a plan view of a portion of one side of the apparatus opposite to that shown in Fig. 1; Fig. rlis a more or less diagrammatic View taken 'in a horizontal plane and illustrat- 1l ing the power driven connections and gearing of the apparatus; and Fig. 8 is a more or less diagrammatic View taken upon a vertical plane showing the .power driven connections and gearing of the apparatus.

Now referring'more particularly 'to the drawings, and especially Figs. l1 to 6 thereof, the apparatus shown ltherein comprises a supporting frame or bed I upon which there is mounted the rotatable member 2 upon which the carriage 3 25v is slidably mounted by means of the dove tail slides 4. A casting 5 is bolted to one end of the carriage 3 and vhas an elongated vertical slot through which the bolt 6 extends. The lower end of the bolt 6 carries a roller 6' adapted to 30 bear against the lateral 'face of the segment shaped abutment 'I. The latter is in turn slidably mounted on the base plate 8 which is bolted to the bed I.

An adjustment `screw 9 threadably engages '35 with the casting 5 and carries a nut I0 on its end for engagement with a suitable wrench or tool. A gauge or Vernier II is also carried on the adjusting screw 9 for the purpose oi indi- (cating relative positions of adjustment.v The 40 adjusting screw S'extends through the boss I2 on the slidable plate I3 which is longitudinally movable with respect to the casting 5 and the carriage 3. 'I'hefbolt `Ii passes through the slidable plate I3 and carries a yoke or collar I4 on its lower 45 lend which is in turn resiliently `connected by means of the rod or bar I5-andr the compression spring I6 to the rotatable member 2. The end ofthe rod I5 is mounted in a drilled recess in the rotatable' member 2 and the compression 50 spring VIt bears against the `faceof the rotatable member 2` ladjacent :such drilled hole and its pressure is adjustable by means of the lock nuts I'I bearing against thewasher'on its other end'.

A second adjusting screw I8 is provided'for 55 adjustably regulating the position of the segment 1 with respect to the bed The adjusting screw I8 threadably engages with the base plate 8 and is axially locked in a boss extending downwardly from the base of the segment 1. A tool receiving end IB and a gauge or Vernier 20 are located on the outer end of the adjusting screw I8.

The carriage 3 has an upwardly projecting 'housing 2| in which the cutter shaft 22 is ro-` tatablymounted. A gear shaped cutting tool 23 is located on the upper end of the shaft 22 and adapted to contact with the worm blank 24. The v -teeth of the cutter 23 have such a form and profile as to cut teeth upon the worm 24 according to the molding generating principle.

A Worm wheel 25 is mounted on the lower end of the cutter shaft 22 and meshes wtih a worm 26 carried by the horizontally disposed shaft 21. The shaft 21 is in turn connected to the shaft 29 through the medium of a spline fitting 28. A gear 39 on the end of the shaft 29 meshes with a gear 3|on the parallel y'shaft 32. Apinion gear 33 onthe other end 'of the shaft 32 meshes with the ring gear 34. The shaft 21 is carried by the carriage3 by means of the bearings 35 and 36 mounted on its under side. The shafts 29 and 32 are journalled in the bearings 31 and 38 respectively which in .turn are mounted upon the rotatable member 2. The ring gear 34 is mountedon the upper end of the vertical tapered drive shaft 39 extending through and rotatable with respect to the rotatable member 2.

Directing attention to Figs. 1 and 6, the work or Worm blank 24 is carried in a headstock 40 which is slidably mounted upon the bed I and is movable thereover by means of the adjusting screw 4 I.

The worm blank 24 is mounted in a suitable rotatable support or arbor 42 to which is connected the worm wheel 43. The latter meshes uwith a worm 44 on the shaft 45 which in turn is connected through the spline fitting 46 to the shaft 41. The shaft 41 is geared to the drive motor &1 through the gears 48 and 49. Another shaft 5|,parallel to the work driving shaft 41 is connected thereto through the gear 52 mounted on the shaft 41, the idler gear 53 and the gear 54 mounted on the shaft 5|. The shaft 5| is connected to a counter shaft 55 through a set of change gears 56, 51 and 58.

Thecounter shaft 55 is connected to the vertical shaft 39 by means of the worm 59 and worm wheel 69.

From the above description, it will be seen that the drive motor 'operates to rotate both the worm 24 and the cutter 23 in timed relation. The ratio of this timed relation can of course be varied by means of the change gears 55, 51 and 5B.

A speed reducing, reversible drive motor 6| is connected to the shaft 62 through the gears 63 and 64. 'Ihe shaft 62 is in turn connected to the rotatable member 2 through the worm 65 and the worm wheel 6G. Thus the motor 6| is effective to vrotate the rotatable member 2, together `with the slidable carriage 3 about the axis of the `rotatable member 2, which of course is a fixed axis, with respectto the other parts of the machine. Of course as the rotatable member 2 is yrotated about its axis, the roller 6' will bear against the face of the segment 1 and will thereby control the arc through which the axis of the cutter 23 passes. Inclined plates 10 and 1| which are in effect portions of the face of the segment 1 are 'mounted on each end of the latter and are inclined outwardly from the inner, lateral face of thes'egment 1. The inclined plates 10 and 1| f the length of the Worm thread cut.

Vswitches 12 and 13 are of course connected in are for the purpose of controlling the initial movement of the cutter as it comes in contact with the worm blank and operate to bring the cutter in' gradually to the full cutting depth at the beginning of the cut and at the beginning of the rotation of the rotatable member 2. Limit switches 12 and 13 are provided adjacent each end of the segment 1 and are adapted to be contacted by a portion of the casting 5 carried by the slidable carriage 3, so that such limit switches will be actuated each time that the rotatable member travels through an arc corresponding to The limit customary manner to the reversible motor 6|. After 'the rotatable member 2 carries the axis of the cutter 23 once across the face of the worm blank 24, the Worm thread cut is nished, the motor 6| is automatically stopped, and a new worm blank is loaded in the machine and then cut-upon reverse rotational movement of the rotatable member v2.

` It'v will thus be'seen that when the center of the arc of the segment 1 coincides with the fixed center-or axis of the rotatable member 2, that the axis of the cutter 3 will then be caused to travel through a true arc, or an arc vwhose radius is constant. But if the segment 1 is moved away fromthe-xed axisof the rotatable member 2, or

conversely towards the xed axis, there will re' sult a variationin the` radius yof curvature of the arc through'which the axis of the cutter 23 is traversed. If the segment 1 is moved further away from the xed axis of the rotatable member 2, that is, to a position where the center of its arc falls to the right (with respect to Fig. 7) of the fixed axis, then the curvature of they path of the axis of the cutter 23 will be greater than that of the true arc path. And correspondingly if the segment 1 is moved closer to the fixed center of the rotatable member 2, the curvature of the path of the axis of the cutter 23 will become lessened, or tend 'to straighten out. Since the orbit o'r path of travel of the axis ofthe cutter 23 determines the pitch line of the worm 24, ity -will thus be seen that the curvature and form of the pitch lineof the inished worm can be controlled and regulated by means of adjustment of the position of `the segment 1. l

VIt will thus'be seen that by virtue of the fact thatthe .roller 6 bears against the lateral face of Vthe segment 1, and that the carriage 3 is slidable -with respect to the rotatable member 2, that the axis of the cutter 23 has a vpossible motion toward and away from the axis of the worm 24, and that'this latter motion is Icontrolled by the contour and'lrelative position ofv the segment 1 and that the lateral face of the segment 1V (including the inclined end blocks 10 and 1|) functions as a control-line or'templet governing such movementof the axisof Vthecutter 23 with respect to the axis of the worm 24.

In Athe event that a worm of larger diameter is to be cut, or a cutter or cutters of varying sizes are to be used adjustments are provided for the accommodation thereof. These adjustments consist first, in the adjusting screw V4| by means of which the headstock may be moved toward and away from the rotatable member 2,; and secondly, in the adjustingscrew 9 by means of which the relative position .of the slidable carriage 3 on the rotatable member 2 (and accordingly the Aposition ofthe 'axis `of the cutter 23 with respect to the fixed axis of the rotatable member 2) can be adjusted.

aaaaesa It will also bernotedthatthe rotation of the' cutter2-3r possessesy a differential action with respect to the=rotation of: the1 rotatable member'Z. Thatyis to-say, assuming thati the ,ring gear, 34 were heldt stationary whilethe rotatable member 2 is rotated, the cutter 23'Would still-be subject to' rotationaabout'its, own. axis by reason of the fact that the pinion gear 23 would then be given a rotational movement as it walks around the ring gear 3H. Thus, the rotational position of the cutter 23 with respect to its own axis is in timed relation with respect to the rotational position of the rotatable member 2. Therefore, the rotation of the cutter 23 about its own axis, when the drive shaft 5I and counter shaft 55 are operated, is not only in timed relation to the rotation of the worm 24, but also in timed relation to the rotatable member 2, i. e., in timed relation to its position in the curved path or orbit through which the axis of the cutter is traversed.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a machine for cutting worms of the hour glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the worm to be cut, means for traversing the axis of said cutter about a fixed axis parallel thereto and removed from the axis of said worm, means for moving the axis of said cutter toward and away from said iixed axis during such traversing movement, an arcuate templet located on the opposite sid-e of said axis to that of the axis of said cutter, the center of the radius of the are of said templet being disposed toward said fixed axis, and means for connecting said last named moving means to said templet for controlling the movement of the axis of said cutter toward and away from said fixed axis.

2. In a machine for cutting Worms of the hour glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the worm to be cut, means for traversing the axis of said cutter about a fixed axis parallel thereto and removed from the axis of said worm, means for moving the axis of said cutter toward and away from said xed axis during such traversing movement, an arcuate templet located on the opposite side ofsaid axis to that of the axis of said cutter, the center of the radius of the arc of said templet being disposed toward said fixed axis, means for connecting said last named moving means to said templet for controlling the movement of the axis of said cutter toward and away from said iixed axis, and adjustable means for varying the location of said templet with respect to said xed axis.

3. In a machine for cutting worms of the hour glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the worm to be cut, means for traversing the axis of said cutter about a fixed axis parallel thereto and removed from the axis of said worm, means for moving the axis of said cutter toward and away from said fixed axis during such traversing movement, an arcuate templet located on the opposite side of said axis to that of the axis of said cutter, the center of the radius of the arc of said templet being dis- 4. In a machine for cutting worms of the hour glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the worm to be cut, means for traversing the axis of said cutter about a xed axis parallel thereto and removed from the axis of said worm, means for moving the axis of said cutter toward and away from said xed axis during such traversing movement, an arcuate templet located on the opposite side of said axis to that of the axis of said cutter, the center of the radius of the arc of said templet being disposed toward said iixed axis, means for connecting said last named moving means to said templet for controlling the movement of the axis of said cutter toward and away from said fixed axis, and means for rotating said cutter about its own axis posed toward, said xed faxis means for connect-A ing saidflast named moving,y means to said templet; for controlling themovement4 of the axisv of said cutter toward andiaway ,fromsaid' fixedaxis, and.. means'for rotating saidf cutter about itsown axis. in timed ,relation tothe, rateof rotation ofi said in timed relation to the rate of rotation of said worm, and in timed relation with respect to its position in such traversing movement.

5. In a machine for cutting worms of the hour glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the worm to be cut, means for traversing the axis of said cutter about a fixed axis parallel thereto and removed from the axis of said worm, vmeans for moving the axis of said cutter toward and away from said fixed axis during such traversing movement, an arcuate templet located on the opposite side of said axis to that of the axis of said cutter, the center of the radius of the arc of said templet being disposed toward said xed axis, means for connecting said last named moving means to said templet for controlling the movement of the axis of said cutter toward and away from said iixed axis, adjustable means for Varying the location of said templet with respect to said iixed axis, and means for rotating said cutter about its own axis in timed relation to the rate of rotation of said worm.

6. In a machine for cutting worms of the hour i glass type, the combination of a molding generating type gear shaped cutter mounted with its axis normal to the axis of the wormto be cut, means for traversing the axis of said cutter about a xed axis parallel thereto and removed from the axis of said worm, means for moving the axis of said cutter toward and away from said fixed axis during such traversing movement, an arcuate templet located on the opposite side of said axis to that of the axis of said cutter, the center of the radius of the arc of said templet being disposed toward said xed axis, means for connecting said last named moving means to said templet for controlling the movementof the axis of said cutter toward and away from said fixed axis, adjustable means for varying the location of said templet with respect to said xed axis, and means for rotating said cutter about its own axis in timed relation to the rate of rotation of said worm, and in timed relation withrespect to its position in such traversing movement. 1

mounted on said base member and carrying a molding generating type gear shaped cutter with its axis normal to the axis of the Worm to be cut, an arcuate track adjacent said carriage and contacting therewith for controlling the slidable movement of said carriage during rotation of said base member, adjustable means for Varying the location of said track with respect to said xed axis, adjustable means for varying the 1ocation of said carriage with respect to said xed axis, and means for rotating said cutter about its own axis in timed relation to the rate of rotation of said Worm, and in timed relation with 5 

